Method and control arrangement for controlling braking of a vehicle

Abstract

The present invention relates to a method performed by a control arrangement for controlling braking of a vehicle comprising: a service brake system and at least one auxiliary brake system for applying a brake torque to at least driven wheels of the vehicle, driver maneuverable means for requesting brake torque from the service brake system, the method comprising, when a brake torque is requested by the driver, and when a temperature of a friction brake of the service brake system increases, or is expected to increase: reducing brake torque applied by the service brake system, and increasing brake torque applied by the at least one auxiliary brake system such that the total resulting brake torque corresponds to the driver requested brake torque. The invention also relates to a control arrangement, a computer program, a computer-readable medium and a vehicle comprising a control arrangement.

1 . A method performed by a control arrangement for controlling braking of a vehicle, the vehicle comprising:
 a service brake system comprising friction brakes for applying a brake torque to at least non-driven wheels of the vehicle;   at least one auxiliary brake system for applying a brake torque to at least driven wheels of the vehicle; and   driver maneuverable means for requesting a brake torque to be applied by the service brake system,   the method comprising, when a first brake torque is requested by a driver by means of the driver maneuverable means, and when a temperature of a friction brake of the service brake system increases, or is expected to increase, to a first temperature:
 reducing a brake torque applied by the service brake system; and 
 increasing a brake torque applied by the at least one auxiliary brake system such that the total resulting brake torque corresponds to the requested first brake torque. 
   
     
     
         2 . A method according to  claim 1 , wherein part of the brake torque requested by the driver by means of the driver maneuverable means is applied by the at least one auxiliary brake system, wherein the maximum available brake torque to be applied by the at least one auxiliary brake system is limited to a first torque limit,
 the method further comprising:
 increasing the first torque limit to a second, higher, torque limit when the temperature of a friction brake of the service brake system increases, or is expected to increase, to a first temperature. 
   
     
     
         3 . A method according to  claim 1 , further comprising, when the first brake torque is requested:
 applying a part of the first brake torque by means of the at least one auxiliary brake system; and   increasing the part of the first brake torque applied by means of the at least one auxiliary brake system when the temperature of the friction brake of the service brake system increases, or is expected to increase, to the first temperature.   
     
     
         4 . A method according to  claim 1  further comprising:
 increasing a part of the first brake torque being applied by means of the at least one auxiliary brake system based on the extent to which the temperature of the friction brake of the service brake exceeds the first temperature, and/or a rate of change of the temperature of a friction brake of the service brake system. 
 
     
     
         5 . A method according to  claim 4 , further comprising:
 increasing the brake torque applied by the at least one auxiliary brake system by a first increase when the temperature of a friction brake of the service brake system increases to the first temperature; and   increasing the brake torque applied by the at least one auxiliary brake system by a second, higher than the first, increase when the temperature of the friction brake of the service brake system increases to a second, higher than the first, temperature.   
     
     
         6 . A method according to  claim 1 , further comprising:
 increasing the first temperature at which the brake torque applied by the at least one auxiliary brake system is increased when data relating to the upcoming road in front of vehicle indicates a reduced need for brake torque.   
     
     
         7 . A method according to  claim 1 , further comprising:
 increasing the brake torque applied by the at least one auxiliary brake system when it is estimated that the temperature of a friction brake of the service brake system will exceed the first temperature within a first period of time.   
     
     
         8 . A method according to  claim 7 , wherein the temperature of the service brake system is estimated at least partly based on information related to the inclination of the upcoming road in front of the vehicle. 
     
     
         9 . A method according to  claim 7 , wherein the temperature of the service brake system is estimated at least partly based on a current driver behavior, wherein it is assumed that the driver maintains a current behavior during the period of time for which the temperature is estimated. 
     
     
         10 . A method according to  claim 1 , the driver maneuverable means being a brake pedal, wherein the driver requests brake torque by depressing the brake pedal. 
     
     
         11 . A method according to  claim 1 , wherein the temperature of the service brake system is an estimated temperature, and/or a temperature obtained through the use of a temperature sensor. 
     
     
         12 . A control arrangement for controlling braking of a vehicle, the vehicle comprising:
 a service brake system comprising friction brakes for applying a brake torque to at least non-driven wheels of the vehicle;   at least one auxiliary brake system for applying a brake torque to at least driven wheels of the vehicle; and   driver maneuverable means for requesting a brake torque to be applied by the service brake system,   the control arrangement being configured to, when a first brake torque is requested by a driver by means of the driver maneuverable means, and when a temperature of a friction brake of the service brake system increases, or is expected to increase, to a first temperature:
 reduce a brake torque applied by the service brake system; and 
 increase a brake torque applied by the at least one auxiliary brake system such that the total resulting brake torque corresponds to the requested first brake torque. 
   
     
     
         13 . A vehicle comprising a control arrangement for controlling braking of the vehicle, the vehicle comprising:
 a service brake system comprising friction brakes for applying a brake torque to at least non-driven wheels of the vehicle;   at least one auxiliary brake system for applying a brake torque to at least driven wheels of the vehicle; and   driver maneuverable means for requesting a brake torque to be applied by the service brake system,   the control arrangement being configured to, when a first brake torque is requested by a driver by means of the driver maneuverable means, and when a temperature of a friction brake of the service brake system increases, or is expected to increase, to a first temperature:
 reduce a brake torque applied by the service brake system; and 
 increase a brake torque applied by the at least one auxiliary brake system such that the total resulting brake torque corresponds to the requested first brake torque. 
   
     
     
         14 . A computer program product stored on a non-transitory computer-readable medium, said computer program product for controlling braking of a vehicle, the vehicle comprising: a service brake system comprising friction brakes for applying a brake torque to at least non-driven wheels of the vehicle; at least one auxiliary brake system for applying a brake torque to at least driven wheels of the vehicle; and driver maneuverable means for requesting a brake torque to be applied by the service brake system, wherein said computer program product comprising computer instructions to cause one or more computing devices to perform the following operation when a first brake force is applied to the vehicle by means of the auxiliary brake system and when an indication of an instability condition associated with a coming road section is detected:
 initiate a transfer of at least a part of the first brake force applied to the vehicle by the auxiliary brake system to, instead, be applied by the foundation brake system prior to reaching the coming road section.   
     
     
         15 . (canceled) 
     
     
         16 . A control arrangement according to  claim 14 , wherein part of the brake torque requested by the driver by means of the driver maneuverable means is applied by the at least one auxiliary brake system, wherein the maximum available brake torque to be applied by the at least one auxiliary brake system is limited to a first torque limit,
 the method further comprising:
 increasing the first torque limit to a second, higher, torque limit when the temperature of a friction brake of the service brake system increases, or is expected to increase, to a first temperature. 
   
     
     
         17 . A control arrangement according to  claim 14 , further configured to, when the first brake torque is requested:
 apply a part of the first brake torque by means of the at least one auxiliary brake system; and   increase the part of the first brake torque applied by means of the at least one auxiliary brake system when the temperature of the friction brake of the service brake system increases, or is expected to increase, to the first temperature.   
     
     
         18 . A control arrangement according to  claim 14  further configured to:
 increase a part of the first brake torque being applied by means of the at least one auxiliary brake system based on the extent to which the temperature of the friction brake of the service brake exceeds the first temperature, and/or a rate of change of the temperature of a friction brake of the service brake system. 
 
     
     
         19 . A control arrangement according to  claim 18 , further configured to:
 increase the brake torque applied by the at least one auxiliary brake system by a first increase when the temperature of a friction brake of the service brake system increases to the first temperature; and   increase the brake torque applied by the at least one auxiliary brake system by a second, higher than the first, increase when the temperature of the friction brake of the service brake system increases to a second, higher than the first, temperature.   
     
     
         20 . A control arrangement according to  claim 14 , further configured to:
 increase the first temperature at which the brake torque applied by the at least one auxiliary brake system is increased when data relating to the upcoming road in front of vehicle indicates a reduced need for brake torque.   
     
     
         21 . A control arrangement according to  claim 14 , further configured to:
 increase the brake torque applied by the at least one auxiliary brake system when it is estimated that the temperature of a friction brake of the service brake system will exceed the first temperature within a first period of time.